Tallgrass Prairie

Tallgrass prairie once covered parts of 14 states in the Midwest, including about 85% of Iowa. Today, less than 0.1% of the original tallgrass prairie remains in Iowa.

Tallgrass prairie is a fire-dependent ecosystem distinguished by tall grasses (up to 10 feet tall), and deep, rich soils. Tallgrass prairie once covered parts of 14 states in the Midwest, including about 85% of Iowa. Today, less than 0.1% of the original tallgrass prairie remains in Iowa. Tallgrass prairie plants have extremely deep roots, reaching up to 12 feet below the surface. These roots created the rich soil that is now valued as crop land. The deep roots hold the soil, preventing erosion where prairie plants have become established.

Some common grasses of the tallgrass prairie include big bluestem, Indian grass, switchgrass, and little bluestem. But prairies are much more than just grasses. A diverse variety of forbs, or wildflowers, are vital parts of the tallgrass prairie, too. Prairie wildflowers include prairie violet, pale purple coneflower, false sunflower, lead plant, white prairie clover, showy tick trefoil, prairie blazingstar, round-headed bushclover, stiff goldenrod, heath aster, and countless others. During the growing season, each flush of bloom tends to be taller than the previously blooming species. Spring begins with the small, delicate violets, and blooming plants generally get taller and taller throughout summer, finishing mainly with the tallest members of the sunflower family in the fall. To learn more about the plants of the tallgrass prairie, pick up a wildflower brochure in the visitor center.

Fire is one of the most important forces at work on the prairie — without fire, the grasses and other fire-adapted prairie plants would be shaded out by trees. Fire stimulates the growth of prairie plants by removing last year’s dead plant material, allowing sunlight to reach the black earth that follows the burn and the new shoots emerging from the ground. Fire promotes the sprouting of many prairie plant seeds by removing the outer seed coat. Frequent fires prevent trees from becoming established. Before the arrival of European settlers in the midwest, Native Americans intentionally set fires in late summer and fall to provide the best habitat for animals such as bison, elk, and deer, to reduce the danger of wildfire, to ease travel, and to increase visibility and safety. Today, refuge staff use prescribed fire on the prairie for similar reasons.

Grazing by large mammals such as bison and elk also helps maintain the plant life of the prairie. The grazing process helps stimulate the growth of many prairie plants, particularly grasses. By selectively grazing on grasses, bison and elk promote the growth of wildflowers that get more sunlight and water when the grasses are kept short.

At Neal Smith National Wildlife Refuge (NWR), which is a reconstructed (or replanted) prairie for the most part, more than 200 species of prairie plants have been seeded into former farm fields. After planting, invasive plants may be mowed or sprayed with herbicides to prevent their spread. Prairie plantings are burned to invigorate the growth of fire-adapted prairie plants and to control the plants that aren’t adapted to fire, and therefore don’t belong on the prairie. These plants include non-native types as well as natives that were historically found only in areas that burned less frequently, such as river bottoms.

The refuge also includes about 90 acres of prairie remnants. These areas represent native plant populations that have survived since before the area was settled and plowed. The plants that have survived in these remnants are particularly adapted to the soil types and climate conditions at Neal Smith NWR, so their genetic material is valuable and important to preserve. Seeds are collected from these remnants so the locally adapted genes can be passed on and dispersed throughout the refuge. Prior to the establishment of the refuge, land use on these remnants included fire suppression, intensive grazing, and in some cases plowing or other soil disturbance. Restoring these remnants is a long-term process. We are working hard to remove trees and shrubs, control woody and invasive species using herbicides, and reintroduce fire to the system. In some cases, additional prairie plants are re-introduced.